Depending in the type of leggings you buy, you may need to purchase a size larger. I'm a medium in US sizes and I've found that the leggings with a thicker band fit well in medium sizes but the leggings with a smaller band around the waist tend to run a bit smaller. This has been my experience so far with them though as I still have more leggings on the way. I was actually nervous bc after I ordered a bunch of them I thought to look at reviews on YouTube and the videos I watched had similar issues. Some styles run small... and I though all of them were going to be too small but I was pleasantly surprised! Of all the leggings I've received thus far, theres only been one pair that's a bit too tight and i may consider returning for a bigger size. Overall, I feel they're worth the buy. You may want to buy one pair at first to get a feel of how the sizes fit or order a size up. It really varies on the style. Great leggings! I love mine!
I have purchased several different leggings, and a couple one piece suits because i love the fit and color on these, the leggings are light but hold tight, and the swim suits are so comfortable